A day of speeches and concerts are scheduled in this eastern Canadian city and provincial capital, but the party itself will keep going through October with performances by Celine Dion and Paul McCartney.

Celebrations are expected to start with a salute to Samuel de Champlain, the French explorer who in the spring of 1608 crossed the North Atlantic Ocean and headed up the Saint Lawrence River to establish the city with 30 other men.

Several guests, including Canada's Prime Minister Stephen Harper and his French counterpart Francois Fillon, are expected to attend the ceremonies.

Former French prime ministers Alain Juppe and Jean-Pierre Raffarin, as well as former presidential candidate Segolene Royal also made a trip over. Royal currently governs a region of France, Poitou-Charentes, where Champlain was born.

"Proving that French culture and language has survived here for four centuries, I find that remarkable," Royal told AFP, noting a fraternity between Quebec and France that was echoed in a speech by Alain Juppe, the mayor of Bordeaux on Wednesday during a ceremony welcoming to Quebec the Belem, France's oldest tall sailing ship.

Around 11 am (1500 GMT) Thursday, the supposed hour of Champlain's arrival on these shores, bells are set to chime throughout Canada.

That would be followed by a commemoration and concert with singers Robert Charlebois and Diane Dufresne.

Later, official festivities are expected to wrap up with a massive fireworks display set to music, said to be the largest ever pyrotechnics show in Canada.

Protests, however, also threaten the fun, with municipal unions in the midst of contract negotiations threatening to seek attention to their plight, and pacifists announcing their intentions to protest a military parade's inclusion in the program.

One group is planning to celebrate in its own way the 400 years of French-speaking peoples in North American on the sidelines of the main event. Promoters of the side show have chided main event organizers for focusing too much on the party, and not enough on its historical basis.

Quebec separatists meanwhile have criticized Canada's federal government for suggesting the festivities are not just a celebration of Quebec City's roots, but also a celebration of the beginnings of Canada.

Beyond the scandals, however, thousands were eager to celebrate in the streets of the old city.

"Quebec City has never been more beautiful. We should be proud of our accomplishments," said Quebec premier Jean Charest.